1. Technical Field
The present invention relates to an inkjet recording method capable of obtaining a high quality image.
2. Related Art
An ink jet recording method is a printing process for printing by letting ink droplets fly and attach to a recording medium such as paper. According to recent innovative progress in ink jet recording technology, the ink jet recording method has been also used in the field of highly fine printing that was achieved by silver halide photography or offset printing before. With this, an ink for ink jet recording has been developed so that an image having glossiness similar to that achieved by silver halide photography can be formed by the ink jet recording on so-called exclusive paper, which is a recording medium having high gloss being equal to that of photographic paper or art paper used in the fields of silver halide photography and offset printing. In addition, ink for ink jet recording that can achieve an image quality, even on plain paper, similar to that achieved by silver halide photography has been developed.
Incidentally, desk top publishing (DTP) has been spreading in recent years, in particular, in the printing field, with technology for forming an image from digital data becoming widespread. Even when printing is carried out by DTP, a proof for color proofing is preliminarily prepared in order to confirm the glossiness and color impression of the actual printed matter. The ink jet recording system is applied to the output of the proof, and exclusive paper for ink jet recording is usually used as the recording medium since high color reproducibility and high color stability of the printed matter are required in DTP.
A proof sheet, which is exclusive paper for ink jet recording, is produced so as to exhibit glossiness and color impression similar to those of the actual output printed on printing paper. Thus, the material of the exclusive paper is properly adjusted depending on the type of printing paper. However, production of exclusive paper that can correspond to all of the various types of printing paper causes an increase in manufacturing cost. Accordingly, in application to color proofing, it is desired, from the technical viewpoint, to conduct ink jet recording on printing paper rather than on exclusive paper. Furthermore, if it is possible to conduct ink jet recording directly on printing paper, not on exclusive paper, for providing a final proof sample, this can significantly decrease the cost of the proof and therefore is desired from the economical viewpoint. In addition, synthetic paper prepared by mixing an inorganic filler and the like with a polyethylene resin, a polypropylene resin or a polyester resin and then forming the mixture into a film with a void structure is widely used in the printing field. The synthetic paper is excellent in recyclability and thereby has recently received widespread attention as an environment-friendly material. It is desired to record on such synthetic paper, from the environmental viewpoint. Further, for the purpose of outdoor advertisement, it is desired to record on a plastic film which does not have a void structure.
The printing paper is a coated paper having a coating layer on the surface for receiving oil-based ink and has a characteristic that the coating layer is poor in ink-absorbing ability against aqueous ink on the coating layer. Therefore, in the use of aqueous pigment ink, which is usually used in ink jet recording, bleeding or beading unevenness may occur in an image because of low permeability of the ink into the recording medium (printing paper). Further, with respect to not only a plastic film which does not have a void structure but a synthetic paper which has a void structure, bleeding or beading unevenness may occur in an image because of a poor ink-absorbing capacity against an aqueous ink on the coating layer.
In view of the above-mentioned problems, for example, JP-A-2005-194500 discloses a pigment ink that has decreased bleeding and also excellent gloss with exclusive paper by including a polysiloxane compound as a surfactant and an alkanediol, such as 1,2-hexanediol, as a solubilization aid. In addition, JP-A-2003-213179, JP-A-2003-253167, or JP-A-2006-249429 proposes that permeability of ink into a recording medium is controlled by adding glycerin, a diol such as 1,3-butanediol or a triol alcohol solvent such as pentanetriol to the ink for forming a high-quality image.
In JP-A-2009-286998 and JP-A-2009-269964, an ink composition which can obtain a high quality image and suppress occurrence of curl is proposed.
JP-A-2005-88238 proposes a liquid composition which contains a modified polyamine but does not contain a colorant, in which the composition is capable of a good cleaning operation with good color and glossiness, and is adhered on a recording medium with an ink composition, however, which is completely different from the ink composition used in the recording method of the invention, from the viewpoint of configuration and effect.
JP-A-2007-261206 provides an ink set which is capable of achieving high fixability, or securing optical density and preventing bleeding at high speed printing, and describes that the ink set contains polyallylamine, however, which is completely different from the ink composition used in the recording method of the invention.
JP-A-2010-691 provides an inkjet recording method where a line head is used and there is excellent color bleeding resistance and describes that a fixing liquid used in the recording method contains polyallylamine, which is completely different from the ink composition used in the recording method of the invention.
JP-A-2010-115854 discloses a printing method including processes of drying, and applying a color ink, a resin ink and a reaction ink, to print an image and describes that the reaction ink used in the printing method contains polyallylamine, which is completely different from the ink composition used in the recording method of the invention.
The present inventors have found that a high-quality image free of bleeding or beading can be formed, in particular, with excellent granularity and curl suppression even in a case of use of various recording media, in particular, a non- or low absorbable recording medium, by using an inkjet recording method using a clear ink composition, which includes processes of applying a clear ink composition and of heating the applied clear ink composition, in which the clear ink composition contains an amino group-containing resin, water, a sparingly water soluble alkanediol, and a wetting agent which is solid at 20° C. and 60% relative humidity.